NeuroToxicology

Widespread exposure to multiple pesticides might potentially represent a genotoxic risk to humans. However the effects of these mixtures are largely unknown. Genotoxicity is a key characteristic of carcinogens, and its assessment represents an important component of the overall safety assessment of pesticides. In the present study, in vitro micronucleus test on intestinal Caco-2 human cells was performed according to OECD TG 487 in order to ascertain the genotoxicity of ten commonly used pesticides (dose range 0-100 mg L-1), tested as individual pesticides or mixtures. Significant dose-related increases in micronuclei were observed for exposures to lambda-cyhalothrin, tebuconazole, glyphosate, deltamethrin, fluopyram and the synergist piperonyl butoxide. Significant increases of micronuclei were also observed at different doses for cypermethrin, acetamiprid and cyprodinil, however these increases were not dose-dependent. Imazalil genotoxicity could not be analyzed due to confounding of high cytotoxicity even at low doses. Results show that the co-formulant piperonyl butoxide was genotoxic to human cell lines at all tested doses. Moreover, glyphosate, acetamiprid and fluopyram showed genotoxic effects at concentrations of 0.01-1.0 mg L-1. Although previously reported to be not genotoxic cyprodinil and deltamethrin were observed to be genotoxic to Caco-2 cells. A combination of 3 prioritzided pesticides (acetamiprid, glyphosate, tebuconazole) showed genotoxic effects even at the lowest dose. A combination of 8 prioritized pesticides showed genotoxicity at the highest dose. No synergistic interactions in micronuclei formation were evident in either the mixture of 3 or 8 prioritized pesticides. This study provides important information on the genotoxicity of different widely used pesticides and confirms the validity of a component-based approach in genotoxicity assessment of pesticide mixtures. This study was performed as part of the EU SPRINT (Sustainable Plant Protection Transition: A Global Health Approach) project.

Mosquito-borne diseases such as dengue, chikungunya, and malaria remain major public health challenges in South Asia, particularly in Bangladesh, where mosquito repellents are widely used as primary preventive tools. This study presents a comparative evaluation of commonly used repellent products, including mosquito coils, liquid vaporizers and aerosols, DEET-based creams, and natural formulations, focusing on their efficacy, protection duration, and potential health risks. Efficacy was assessed using controlled laboratory methods, including chamber-based exposure and arm-in-cage tests against Aedes aegypti (Barnard & Xue, n.d.). Safety was evaluated through in vivo toxicological analysis in a rat model, incorporating clinical observations, hematological and biochemical profiling, and histopathological examination. The results indicated an overall mean effectiveness of 85%, with DEET-based creams demonstrating the highest efficacy (95%), while natural repellents showed the lowest (70%). Mosquito coils provided the longest protection duration ([~]10 hours) but were associated with the highest health risk due to combustion-related emissions. Vaporizers and aerosols offered moderate efficacy with moderate health risk. Toxicological findings revealed that coil exposure induced significant respiratory stress, elevated liver enzymes (ALT, AST), increased leukocyte count, and notable lung tissue damage. Vaporizer and aerosol exposure resulted in mild physiological changes, whereas DEET-based and natural repellents showed minimal systemic toxicity. Overall, the study highlights a clear trade-off between efficacy and safety across repellent types. These findings emphasize the need for informed product selection, stronger regulatory control, and the development of safer, cost-effective, and sustainable mosquito repellent technologies for effective vector control in endemic regions.

Neonatal meconium provides a non-invasive matrix for assessing prenatal or near-birth exposure to environmental contaminants. Although microplastics and metals have each been reported in human biological samples, integrated assessments of concurrent particle and metal exposure in meconium remain scarce, particularly in South Asia. In this cross-sectional biomonitoring study, meconium from 30 Cesarean-delivered neonates born in Dhaka, Bangladesh, was analyzed for microplastic occurrence, morphology, and polymer composition using stereomicroscopy, scanning electron microscopy, and Raman spectroscopy, and for fifteen metals using inductively coupled plasma mass spectrometry. Maternal breast milk from a subset of lactating mothers was analyzed as a complementary maternal exposure context. Microplastics were detected in all analyzable meconium samples (n=28), with a median burden of 149 particles/g wet weight, dominated by polyethylene terephthalate fragments and nylon fibers. All fifteen measured metals were also detected in all analyzable meconium samples, with median Pb and Cr concentrations of 1.18 and 3.92 ug/g dry weight, respectively. No microplastic-metal associations remained significant after multiple-testing correction, suggesting partly distinct exposure or accumulation pathways. Here, we show that neonatal meconium captures concurrent microplastic and metal exposure in an urban South Asian birth cohort. This study provides one of the first integrated meconium-based assessments of concurrent microplastic and metal exposure from the region and highlights meconium as a practical matrix for early-life biomonitoring.

INTRODUCTION: Alzheimers disease (AD) is a multifactorial disorder, yet current research largely focuses on downstream biomarkers with limited attention to environmental contributors. Experimental studies suggest that per and polyfluoroalkyl substances (PFAS) may contribute to neuroimmune and neurodegenerative pathways relevant to AD. OBJECTIVE: To examine associations between PFAS exposure and neuroimmune and AD related plasma biomarkers in cognitively unimpaired rural adults. METHODS: In a cross sectional pilot study (n=48), serum concentrations of 33 PFAS were measured, including four legacy compounds (PFOS, PFHxS, PFOA, PFNA). Plasma neuroimmune related (ITGB2, SMOC1, TREM2, GFAP) and AD related biomarkers (Ab42/40, ptau217) were detected using proteomic analysis. RESULTS: PFOS showed moderate associations with ITGB2, SMOC1, and Ab42/40 in unadjusted analyses, which attenuated after adjustment for age. PFOA and PFNA demonstrated consistent inverse associations with TREM2 before and after adjustment. DISCUSSION: Findings suggest possible compound specific PFAS associations with immune and amyloid related biomarkers, supporting further investigation in longitudinal and PFAS mixture based studies.

Silver has been used as a biocide for centuries, mostly in health-oriented applications. However, as a biocide, silver is toxic not only to its intended targets, mainly bacteria and fungi, but also to all living cells. Because of this toxicity, it is desirable to use forms of silver that maximize the required biocidal activity while minimizing the amount of silver that will be released in the environment at the end of life of the product. Silver nano objects are a good compromise for such requirements. The high surface to volume ratio allows for good reactivity and thus good biocidal activity, while the small amount of silver present in nano objects allows for a limited environmental release at the product end of life. In this work, we tested three types of silver nano objects. The first type, polyvinylpyrrolidone-coated silver nanoparticles (nAg-PVP) were used as a control nanoparticle, as this type of nanoparticle is now widespread. We also manufactured and tested maltodextrin-coated silver nanoparticles (nAg-MD) and micrometric (20 {micro}m in two dimensions and a few nanometers in the third one) silver flakes ({micro}AgSF). For these three silver nano objects, we investigated the biocidal activity by stringent tests using both Staphylococcus aureus and Escherichia coli as target bacteria. In addition, we investigated toxicity on mammalian macrophages or keratinocytes cell lines, as well as on an insect hemocyte cell line. Our results showed that the two innovative silver nano objects (nAg-MD and even more {micro}AgSF), showed both a better bactericidal activity and a lesser toxicity than the reference nAg-PVP nanoparticles. In addition, we also checked that beyond toxicity, the silver nano objects did not induce an inflammatory reaction, making them safer to use.

The ubiquitously occurring food contaminants altenuene (ALT) and tentoxin (TEN) are recognized as emerging Alternaria mycotoxins, yet substantial data gaps remain when it comes to their toxicological behavior and toxicokinetic characteristics. This study aimed to compare and generate quantitative data on their hepatic metabolism and to obtain semi-quantitative insights into their metabolite profiles. To this end, primary rat and human hepatocytes were incubated with 10 {micro}M ALT or TEN over multiple time points up to 4 h. Both substrate depletion and metabolite identification revealed pronounced interspecies differences. The extent of ALT metabolism was significant, with an 88% and 57% decrease in rat and human hepatocytes after 4 h, respectively. In contrast, TEN showed extensive biotransformation in rats (67%) but only modest turnover in humans (27%) over the same period. Hepatocellular clearances were consistently higher for ALT than TEN, with hepatic extraction ratios indicating intermediate extraction for ALT and low extraction for TEN. High-resolution mass spectrometry combined with targeted analysis of selected metabolites annotated phase II conjugation as the predominant metabolic pathway for ALT and phase I oxidative metabolism for TEN, including mono- and double-metabolized species for the latter. Overall, these results provide a comprehensive characterization of ALT- and TEN-metabolism in hepatocytes, offering a foundation for future studies on their toxicological relevance and impact on human health.

The foodborne mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) have been associated with several adverse effects, including cytotoxicity, genotoxicity, endocrine disruption, and immunomodulation. As these endpoints are typically observed in vitro at micromolar concentrations, the question arises whether such levels are attainable in exposed humans. To address this data gap in chemical risk assessment, a physiologically based kinetic (PBK) model was developed to predict internal exposure doses to AOH and AME in humans. As input parameters, kinetic constants for hepatic glucuronidation were obtained in vitro by incubating Sprague Dawley rat and human liver S9 fractions with 0.5-50 M AOH and 0.5-20 M AME, demonstrating rapid biotransformation in both species. Intestinal absorption of AME and physicochemical parameters were estimated using quantitative structure-activity relationship (QSAR) models. Sensitivity analysis identified parameters describing hepatic glucuronidation and gastrointestinal uptake as among the most influential, confirming the importance of their reliable estimation. The PBK model was evaluated against available rodent toxicokinetic data and subsequently extrapolated to humans. Ultimately, the currently available exposure estimates published by EFSA in 2016 were applied to predict target tissue concentrations, which were compared to points of departure (PoDs) for relevant toxicological endpoints. Even in the most susceptible group of male toddlers, predicted internal concentrations (10-4 M range) were approximately four orders of magnitude below the respective PoDs. Consequently, under the applied exposure assumptions and considering the compounds as isolated chemicals, AOH and AME are not expected to reach systemic or tissue concentrations associated with the investigated effects.

The early developmental environment plays a critical role in the etiology of cardiovascular diseases (CVDs), but underlying molecular mechanisms are poorly understood. Exposure to per and polyfluoroalkyl substances (PFAS) are linked to various CVDs, but effects of developmental PFAS exposures on the human heart remain unclear. Using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), the objective of this study was to investigate the effects of PFAS exposure during cardiac differentiation on gene expression and function of cardiomyocytes. We exposed two hiPSC lines (one male and one female donor) to perfluorooctanoic acid (PFOA), a common and ubiquitous PFAS (0.05, 0.5, 5, 50, 100, 150, 200 M), followed by assessment of cellular number and pluripotency marker expression. PFOA exposure for 72 hours had no significant effects on hiPSC pluripotency, and modest inhibition of proliferation was observed only at the highest concentration. hiPSCs were then differentiated into ventricular cardiomyocytes in the continued presence or absence of PFOA (0, 0.5, 5, 50 M) using an established small molecules protocol. Optical mapping studies using voltage and calcium-sensitive dyes revealed dose and cell line-specific effects of PFOA on cardiomyocyte voltage and calcium dynamics that were still present 10 days after cessation of exposure. Patch clamping studies demonstrated small but significant reductions in repolarizing IKr currents with 5{micro}M PFOA exposure in cardiomyocytes from both donors. Using RNA-seq, we found that exposure to PFOA led to significant changes in transcriptional pathways related to lipids and lipoproteins in the female hiPSC-CM. In the male hiPSC-CM, we observed significant effects on developmental pathways and calcium homeostasis. Thus, we found that environmentally relevant PFOA exposure during cardiomyocyte differentiation affects the electrophysiological properties and transcriptome of hiPSC-CM even after cessation of exposure, with effects that differ by donor cell line. These findings provide direct experimental evidence that transient developmental exposure to PFOA can durably reprogram human cardiomyocyte function, supporting a developmental origin of PFAS-associated cardiovascular risk. Impact StatementThese studies demonstrate that exposure to environmentally relevant levels of PFOA during the differentiation of hiPSCs into cardiomyocytes alters cardiac gene expression and function, with effects that persist beyond cessation of exposure.

Ethylene oxide is a widely used industrial chemical,yet evidence linking its exposure to Parkinsons disease remains limited.Using data from participants in the United States,we examined whether exposure to ethylene oxide is associated with Parkinson's disease.This cross-sectional study included 8,430 adults from the National Health and Nutrition Examination Survey (NHANES) collected between 2013 and 2020.Information on demographic characteristics,socioeconomic factors,lifestyle behaviors,body mass index,sedentary time and major chronic conditions was analyzed. Levels of hemoglobin ethylene oxide adducts,a biomarker of ethylene oxide exposure, were evaluated in relation to Parkinsons disease using statistical modeling approaches.After accounting for potential confounding factors,higher levels of ethylene oxide exposure were associated with an increased likelihood of Parkinson's disease.The association followed a positive and linear pattern.These findings provide new population-based evidence suggesting that ethylene oxide may be linked to Parkinsons disease and highlight the need for further studies to confirm causality and to better understand the biological mechanisms involved.

INTRODUCTIONMounting evidence support exposome influences on brain function and health, complementing genome influences. Understanding the molecular imprint of exposome on brain metabolism and the biochemical communication between the body and brain can impact our fundamental understanding and treatment of neuropsychiatric diseases. METHODSLeveraging two complementary metabolomics platforms, we classified 1400 features in 514 brains from the ROSMAP collection. We evaluated the origin of these compounds using literature and databases. We correlated those metabolites with cognitive function using linear models. RESULTSWe identified over 230 non-endogenous compounds in the brain, including 103 drugs and metabolites, 120 dietary and microbial products and possibly 15 compounds from environmental exposures. Over 20 dietary and gut microbial compounds showed associations with cognition. DISCUSSIONComprehensive profiling of chemicals in the brain and the link to cognitive function provides foundational work to connect body and brain in the study of AD and related dementias.

Railway catenary sparking generates airborne ultrafine particles (UFPs) that may pose health risks due to their metallic composition and ability to penetrate deep into the alveolar region of the lungs. Copper, widely used in wires and pantographs, is a major component of these emissions, making copper-rich particles common in railway environments such as subways. However, exposure levels and health impacts remain poorly characterized, and localized hotspots may represent an underrecognized risk in densely populated areas. This study investigated the toxicity of copper UFPs under realistic dosimetry and deposition conditions. Copper UFPs were generated using a spark discharge generator and applied to two in vitro lung models: a 3D co-culture of Calu-3 epithelial cells, THP-1-derived macrophages, and EA.hy926 endothelial cells, and a monoculture of A549 alveolar epithelial cells. Cells were exposed at the air-liquid interface (ALI) using an automated platform to mimic inhalation exposure and UFPs deposition. Copper deposition ranged from 6.5 to 41 ng/cm2, within occupationally relevant levels. A549 cells showed cytotoxic responses consistent with previous studies, whereas the 3D co-culture model revealed broader adverse effects, including inflammation, impaired epithelial barrier integrity, oxidative stress, and early DNA damage. Inflammatory activation also differed between models: A549 cells mainly exhibited transcriptional responses, while the 3D model showed significant secretion of IL-6 and IL-8, associated with interferon signaling. These findings highlight the potential health risks of copper UFPs from railway systems and emphasize the need for improved characterization of UFP exposure in environmental and occupational railway settings.

Benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon (PAH), is a widespread environmental toxicant and potent ligand of the aryl hydrocarbon receptor (AHR). Yet, how early developmental exposure to BaP influences human neurodevelopment remains poorly understood. We first examined AHR expression dynamics during human embryonic stem cell (ESC)-derived cerebral organoid development and found that AHR expression was highest at the ESC stage and declined during subsequent differentiation, suggesting a potential window of heightened susceptibility to AHR-mediated environmental perturbations. Based on this observation, ESCs were exposed to BaP (0.1, 1 M) for 7 days prior to organoid generation. BaP exposure did not alter proliferation, cell death, or global transcription of ESCs but increased expression of a subset of AHR target genes. Remarkably, however, organoids derived from BaP-exposed ESCs exhibited profound morphological defects resulting from premature neurogenesis, characterized by disrupted neural rosette organization, reduced EOMES intermediate progenitors, and increased BCL11B neurons. Pharmacological inhibition of AHR with CH-223191 attenuated AHR activation and rescued the progenitor-neuron imbalance. These findings identify AHR signaling as a critical upstream mediator of BaP-induced developmental neurotoxicity and highlight the vulnerability of early pluripotent stages to environmental insults.

Pollution of aquatic environments poses an increasingly severe threat to ecosystems worldwide, and understanding its molecular consequences for aquatic organisms requires extensive research and the development of advanced analytical tools. Phosphoproteomics can be particularly valuable for this purpose, as shifts in phosphorylation states can serve as early molecular indicators of toxic exposure. The cladoceran Daphnia is a keystone species in aquatic ecosystems, linking lower and higher trophic levels, and is therefore widely used as a model organism in ecotoxicology to study biological consequences of pollution. Here, we present a simple and effective strategy to analyse the phosphoproteome of Daphnia magna, a commonly used Daphnia species in ecotoxicology. Following TiO2-based phosphopeptide enrichment and LC-MS/MS analysis, we identified a comprehensive dataset of 3,532 phosphorylation sites across 1,329 phosphoproteins. These proteins were especially involved in signaling pathways and cellular structure and the vast majority have not yet been demonstrated in other Daphnia species. In conclusion, our results demonstrate that a straightforward phosphoproteomic LC-MS/MS workflow in D. magna can serve as a powerful tool for investigating adverse molecular effects caused by anthropogenic pollution, such as microplastics or pharmaceuticals. Statement of significanceThe dataset presented here demonstrates the feasibility of a simple yet effective strategy to perform phosphoprotemics in Daphnia magna, and it will be particularly valuable for future ecotoxicoproteomics research using this model organism.

INTRODUCTION: Alzheimers disease and related dementias (AD/ADRD) arise from cumulative environmental, social, behavioral, and biological influences across the life course. The neural exposome framework conceptualizes how exogenous, behavioral, and endogenous factors interact to shape brain health; however, its application to preclinical AD/ADRD research, particularly in rural populations, remains limited. METHODS: We developed and piloted a community-embedded, decentralized research model to operationalize the neural exposome framework among cognitively unimpaired adults aged 45+ in two rural Midwestern U.S. communities, integrating environmental, social, behavioral, geospatial, and biological measures to evaluate exposure-related neurobiological and cognitive vulnerability. RESULTS: This approach demonstrated high feasibility and acceptability, achieving strong recruitment, retention, data completeness, and multidomain biomarker collection in rural community-based settings DISCUSSION: Pilot findings support the feasibility of neural exposome-informed research in rural U.S. communities and highlight its potential to advance prevention-oriented research on brain health and AD/ADRD.

Lead is a toxic metal ubiquitous in our environment. While dramatic reductions in lead sources have paralleled equivalent decreases in lead-poisoning rates, chronic lead exposure remains a critical public health concern. Childhood lead exposure (at its lowest levels) is liked to changes in cognitive development but less is known about lead's effects on children's brain structure, especially as a result of in utero exposure. We measured prenatal and early-postnatal lead exposure in shed deciduous teeth of 448 9- and 10-year-old children (from 20 United States cities) and linked those lead levels to childhood brain structure, cognition/behavior, and neighborhood- and family-level socioeconomic characteristics. Here we show negative associations between tooth-lead levels and the thickness of the brain's cortex, particularly in regions linked to language processing. With increasing tooth-lead levels, children of lower-income (versus higher-income) families showed steeper declines in receptive vocabulary. Caregiver-reported behavioral problems exhibited similar associations. With in utero exposure linked to adverse neurodevelopmental outcomes (well before lead exposure and its risks are evaluated by healthcare professionals), prenatal screening of maternal lead levels/exposure, coupled with recommended strategies to reduce its placental transmission, may help reduce lead's effects on future generations.

Until now, there has been no animal-free alternative method for predicting chronic inflammation and delivering the associated dose responses, the timing of onset, and the duration of inflammation, as required by regulatory agencies. We present the results of pre-validation of an in-vitro-learned digital twin (InFiniteLungDT) capable of predicting chronic neutrophilic lung inflammation for regulatory use. The method is based on measuring the dynamics of early biological effects in vitro induced by respirable materials or their mixtures, without the need to know their intrinsic properties. We constructed the digital twin(s) for each of the material, for which we have in vivo exposure data. The instillation data set, comprising 49 different nanomaterials, was used as the primary anchor to calibrate the model. Inhalation data set, comprising 7 different nanomaterials, compliant with OECD TG 412, was used to show the general applicability of the method across species and for different exposure scenaria. In total, about 3094 single mouse exposures and 364 rat exposures (and approx. 775/225 non-exposed mouse/rat controls) were used to predict concentration-dependent time-evolved neutrophil influx into the lung. The accuracy (predictive capacity) of LOAEL determination is 93% for instillation and 84% for inhalation exposure. Taking into account the time-to-deliver-result being less than 1 week, this proves that the effect of inhaled material from acute to chronic conditions can be assessed orders of magnitude faster and cheaper than in a reference animal study.

Importance: Alzheimer disease (AD) pathogenesis begins decades before clinical symptoms, yet environmental determinants of early disease risk, particularly during fetal development, remain largely uncharacterized. Prenatal exposure to dichlorodiphenyldichloroethylene (DDE), the primary persistent metabolite of DDT, is a biologically plausible early-life contributor to AD risk given long half-life in human tissue and higher levels observed in AD patients. However, prospective human evidence linking prenatal DDE to midlife AD-relevant outcomes is absent. Objective: To determine whether prenatal DDE exposure is associated with plasma AD biomarkers and cognitive performance in early midlife offspring, and whether APOE {epsilon}4 genotype modifies these associations. Design: Observational cohort analysis nested within the Child Health and Development Studies (CHDS), a population-based birth cohort. Setting: CHDS enrolled pregnant women between 1959-1967 in the San Francisco Bay Area. Participants: Among 367 eligible adult offspring who participated in a follow-up study (2010-2013) at mean age 49.3 years, 179 with available prenatal DDE measurements were included. Main Outcomes and Measures: Prenatal DDE levels from maternal serum. Primary outcomes were plasma A{beta}42/40 ratio and Digit Symbol Substitution Test (DSST) performance. Secondary outcomes included plasma pTau217, GFAP, NfL and APOE genotype. Results: Among 179 participants (56% female; 26% APOE {epsilon}4 carriers), mean prenatal DDE was 47.4 (25.4) ng/mL. Higher prenatal DDE was associated with lower DSST scores ({beta}=-0.021, 95% CI, -0.041 to -0.001, P=0.039) and lower plasma A{beta}42/40 ratio ({beta}=-0.079, 95% CI, -0.133 to -0.024, P=0.005) per ng/mL DDE, adjusting for sex, race, education, and APOE {epsilon}4 status. Associations were strongest among APOE {epsilon}4 non-carriers for DSST ({beta}=-0.033, 95% CI, -0.050 to -0.016, P=0.001) and A{beta}42/40 ratio ({beta}=-0.101, 95% CI, -0.161 to -0.040, P=0.001). No significant associations were observed for pTau217, GFAP, or NfL. Conclusions and Relevance: In this prospective birth cohort study, prenatal exposure to a persistent environmental toxicant was associated with lower plasma A{beta}42/40 ratio and worse cognitive performance in early midlife, consistent with DDE accelerating the preclinical trajectory of AD-related biological changes decades before symptom onset. These findings support a life-course framework for AD risk and identify prenatal DDE as a potentially modifiable determinant of early AD-related pathology amenable to prevention.

Alzheimers disease (AD) is influenced by both genetic risk and environmental exposures, but how these factors interact in human microglia remains unclear. Here, we investigate whether the late-onset AD risk allele APOE4 impacts microglial vulnerability to arsenite exposure. To that end, we used CRISPR/Cas9 to generate an isogenic APOE4+/+ iPSC-derived transcription factor-induced microglia-like cells (iTFM). We demonstrate that APOE4+/+ iTFM exhibit decreased survival following arsenite exposure, as evidenced by a lower LC50 compared to APOE3+/+ controls. Transcriptomic profiling identified arsenite concentration as the primary driver of gene expression changes, while genotype contributed a secondary, distinct component of the response. Weighted gene co-expression network analysis revealed genotype-dependent modules enriched for phagocytic and oxidative stress pathways, including KEAP1-NFE2L2 signaling. These transcriptomic changes were further supported by functional assays. APOE4+/+ iTFM had a high proportion of phagocytic cells and altered mitochondrial phenotypes including increased mitochondrial mass, reduced membrane potential, and reduced superoxide production, all of which were further perturbed by low dose arsenite exposure. These results support a gene-environment interaction-dependent increase in microglial vulnerability via reshaping of transcriptional and functional stress responses, and provide a human cell-based framework for studying environmentally mediated microglial contributions to AD.

Gold is widely distributed in the biosphere, and higher plants growing on geochemically anomalous substrates can accumulate significant amounts of gold. This study reports, for the first time from Goa, the detection, spectroscopic characterisation, and X-ray diffraction analysis of phytoformic gold -- biologically sequestered crystalline gold -- in the above-ground dry litter ash of six tree species (Acacia auriculiformis, Alstonia scholaris, Anacardium occidentale, Artocarpus heterophyllus, Ficus benghalensis, Syzygium cumini) growing on mining dumps within the North Goa Banded Iron Formation (BIF) Belt of the Western Dharwad Craton. Microgravimetric analysis of aqua regia-extracted heavy ash fractions revealed gold concentrations of 275-1100 ppm, two to five orders of magnitude above the crustal background ([~]0.004 ppm). Fourier Transform Infrared (FTIR) spectroscopy of 0.22{square}m membrane-filtered crude extracts confirmed the tetrachloroaurate(III) complex [AuCl{square}]{square} as the dominant dissolved gold species, with the diagnostic 1400-1700{square}cm{square}1 absorption envelope present in all six species. UV-Visible spectrophotometry confirmed chloroauric acid formation with a universal {lambda}max at 372.5{square}nm across all species. Powder X-ray diffraction (XRD) of heavy ash fractions yielded the characteristic FCC metallic gold reflections Au(111), Au(200), and Au(220) in all five species analysed. Application of the Debye-Scherrer equation to the Au(111) reflection (2{theta} = 38.2{degrees}, Cu K) established crystallite sizes of 17.7-31.8{square}nm, confirming that phytoformic gold exists as nanoscale crystalline particles in all species. Ficus benghalensis produced the largest and most crystalline gold nanoparticles (31.8{square}nm) and uniquely exhibited strawberry-shaped isomorphic auriferous siliceous biominerals designated phytoauroliths. The described low-cost protocol -- ashing, aqua regia extraction, membrane filtration, and multi-technique spectroscopic and diffraction confirmation -- constitutes a validated method for rapid biogeochemical gold anomaly detection. Applications in gold phytoextraction and mining waste phytoremediation are discussed.

Background and Purpose: Ambient air pollution is an established risk factor for incident stroke, but whether post-discharge pollutant exposure influences stroke recurrence remains unknown. We investigated the association between post-discharge exposure to six ambient air pollutants and stroke recurrence in patients with acute ischemic stroke. Methods: We analyzed data from 27,346 patients in the CRCS-K-NIH nationwide multicenter registry of acute ischemic stroke patients (2014-2021) with confirmed ischemic stroke, residential address data, and matched air quality records. The primary exposure was the 3-month post-discharge average concentration of PM10, PM2.5, NO2, SO2, CO, and O2, assessed at the district level using inverse-distance weighted interpolation. The primary outcome was stroke recurrence from 3 to 15 months post-discharge. Cause-specific Cox proportional hazards models accounting for the multilevel data structure were used, with all-cause mortality as a competing risk. Restricted cubic splines assessed nonlinear dose-response relationships. Results: During follow-up (median 364.8 days), 765 patients experienced stroke recurrence and 471 died. Among the six pollutants, only SO2 showed a statistically significant association with recurrence (P for overall association in the restricted cubic spline analysis = 0.024). A potential threshold was identified at approximately 8.2 ppb, above which recurrence risk increased progressively (P for non-linearity = 0.095). The association was numerically stronger among older adults ([≥]75 years; P for interaction = 0.051) and women (P for interaction = 0.062). The highest SO2 concentrations were observed in harbor cities (Incheon, Ulsan, Busan), consistent with maritime shipping emissions. No significant associations were observed for the other five pollutants. Conclusions: Elevated post-discharge SO? exposure is associated with increased stroke recurrence risk, particularly in harbor regions and among older adults and women. These findings support incorporating ambient air quality monitoring into secondary stroke prevention strategies.